fix: 移除 Home 页面容器 zIndex，修复客服按钮被遮挡问题

- HomePage.tsx: Container 移除 zIndex={30}
- 客服按钮 zIndex=10，之前被 30 的层级覆盖无法点击
- 移除后不影响页面内部布局

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Co-Authored-By: Claude <noreply@anthropic.com>

src/views/Home/HomePage.tsx

@@ -89,7 +89,7 @@ const HomePage: React.FC = () => {
         overflow="hidden"
       >
 
-        <Container maxW="7xl" position="relative" zIndex={30} px={containerPx}>
+        <Container maxW="7xl" position="relative" px={containerPx}>
           <VStack
             spacing={{ base: 5, md: 8, lg: 10 }}
             align="stretch"